scholarly journals Bulk Solubility and Speciation of Plutonium(VI) in Phosphate-Containing Solutions

1992 ◽  
Vol 294 ◽  
Author(s):  
H. T. Weger ◽  
S. Okajima ◽  
J. C. Cunnane ◽  
D.T Reed
Keyword(s):  
Absorption Spectra ◽  
Accurate Determination ◽  
Absorption Bands ◽  
Initial Ph ◽  
Colloid Formation

ABSTRACTThe solubility and speciation of Pu(VI) with phosphate is being investigated to determine the ability of phosphate to act as an actinide getter. In the initial studies performed, solubility was approached from oversaturation at an initial pH = 4, 10 and 13.4. Absorption spectra were recorded, the solution filtered, and the filtrate analyzed for Pu content. Absorption spectra were obtained at varying phosphate concentrations, and at pH of 2.7 to 11.9. The effect of complexation on the 833 nm Pu(VI) band was characterized. Evidence for three phosphate complexes was obtained for pH < 10, which have absorption bands at 842, 846 and 849 nm. Evidence for colloid formation was observed, but is not conclusive. The possible presence of colloids prevented an accurate determination of true solubility. A concentration of 10−5 to 10−6M Pu(VI) was measured in solutions at pH ≤ 10 that was filtered with a 50 nm filter. Pu(VI)-phosphate complexes predominated at pH ≤ 11.6. At higher pH, however, only hydrolyzed Pu(VI) was detected. At pH = 12, the concentration of Pu(VI) was as high as 10−4M.

Applications of Infrared Methods in the Structural Examination of Synthetic Rubber

1946 ◽  
Vol 19 (4) ◽  
pp. 1113-1123 ◽  
Author(s):  
J. E. Field ◽  
D. E. Woodford ◽  
S. D. Gehman
Keyword(s):  
Absorption Spectra ◽  
Organic Molecules ◽  
Normal Modes ◽  
Structural Variations ◽  
Structural Examination ◽  
Absorption Bands ◽  
Synthetic Rubber ◽  
Modes Of Vibration ◽  
Long Chain

Abstract Infrared absorption spectra have been long recognized as a convenient means for studying the structure of organic molecules. The interpretations of the spectra are based on the energy interactions of the molecule and the radiations which arise from the vibration of the constituent atoms and molecular rotations. For simple or highly symmetrical molecules, the determination of the normal modes of vibration and the calculation of the absorbing frequencies are relatively simple and straightforward. For more complicated organic molecules, this becomes increasingly difficult because with each additional atom, the number of degrees of freedom is increased by three and the determination of the normal modes of vibration becomes practically impossible. However, interpretations can be made to a useful extent through empirical comparisons with the absorption spectra of simpler known structures. The data that have been accumulated by investigators in this field have made it possible to assign rather definite absorption frequencies to some of the chemical linkages and functional groups. These correlations which have appeared in numerous places in the literature are partially reproduced in Table I. Organic compounds generally have strong absorption bands below 1300 cm−1, to which few definite assignments can be made with certainty because the vibrations of many of the atoms of the molecule may be involved rather than a specific part of it. It is clear that such empirical relationships must be relied upon in studying the structural variations of the long chain, complex molecules which occur in butadiene and isoprene polymers and copolymers and other synthetic rubbers. This procedure has been applied to determine the effects of oxidation and of variations in monomers and polymerizing conditions on the structure of synthetic rubber. It is practically certain that physical deficiencies of synthetic rubber are due principally to the structure of the long chain molecules rather than to the chemical nature of the monomers used.

Preparation of U(VI) and Th(IV) alpha-sources from sea and fresh water samples by combining coprecipitation, solvent extraction and electrodeposition procedures

2004 ◽  
Vol 92 (3) ◽  
Author(s):  
R. Zarki ◽  
A. Elyahyaoui ◽  
A. Chiadli
Keyword(s):  
Solvent Extraction ◽  
Fresh Water ◽  
Water Samples ◽  
Sea Water ◽  
Accurate Determination ◽  
Simple Method ◽  
Considerable Saving ◽  
Initial Aqueous Solution ◽  
Initial Ph

SummaryA simple method combining coprecipitation, solvent extraction and electrodeposition for determining uranium and thorium in sea water and fresh water samples is developed. It offers a considerable saving in time, minimising chemical treatment and costs. The analytical procedure consists of enrichment of U and Th by coprecipitation with iron(III) hydroxides and subsequent extraction by diethylether solution and electrodeposition of each actinide in the extracting organic phase in which it was separated.The dependence of the coprecipitation, the extraction-electrodeposition and the overall yields of the above mentioned elements is examined in relation to the initial aqueous solution acidity and various amounts of iron carrier. At an initial pH between 6 and 10, quantitative coprecipitation of U and Th requires use of an Fe(III) quantity which depends on the acidity of these solutions. This quantity varies, under explored conditions, between 10 and 110mg/L. At a starting pH of 11, this coprecipitation becomes almost independent of Fe(III) amounts.The proposed procedure was used to analyse the content of U and Th isotopes in water samples. Recoveries of 60%-93% are obtained for uranium and 63%-86% for thorium. Good resolutions (37-56.5keV) are also achieved under optimum conditions. These resolutions allow to make accurate determination of U and Th isotopes in various water samples.

Dithiolate Mixed with Diimine and it's Metal Effects on Sensors

2014 ◽  
Vol 1021 ◽  
pp. 52-55
Author(s):  
Yong Hui Jia ◽  
Chao Xu
Keyword(s):  
Energy Level ◽  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Spectra ◽  
Electronic Absorption Spectra ◽  
Orbital Energy ◽  
Absorption Bands ◽  
The Relationship ◽  
Orbital Energy Level

Determination of the two Maleinitriledithiolate • phenanthroline-5 ,6-dione Lynn mixed copper (II), zinc (II) complexes MLL' (L=mnty, 1,2 twelve dicyanoethylene-1,2 - thiol ion L '= phen-5, 6-dione, l, 10 - phenanthroline-5 ,6-one o) amine in dimethy-l phthalate (DMF), acetone (Acet.) and chloroform (HCli) electronic absorption spectra corresponding to transitions studied the relationship between the absorption bands in the electronic spectra associated molecular orbital energy level diagram to explore their photographic oxidation characteristics in DMF.

scholarly journals Luminescent determination of residues of trazodon hydrochloride and melatonin after cleaning pharmaceutical equipment

2019 ◽  
pp. 73-81
Author(s):  
O. D. Voitiuk ◽  
A. V. Yegorova ◽  
Yu. V. Scrypynets ◽  
S. N. Kashutskуy ◽  
V. P. Antonovich
Keyword(s):  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Xenon Lamp ◽  
Excitation Spectra ◽  
Absorption Bands ◽  
Limit Of Quantitation ◽  
Trazodone Hydrochloride

A prerequisite for ensuring the quality of medicines is their production in accordance with the rules of GMP (Good Manufacturing Practice for Medicinal Products), one of the most important requirements of which is equipment cleaning. In many cases, the same equipment is used in the production of various preparations. Therefore, to prevent contamination of each of the following drugs, the previous one, it is very important to carry out an effective equipment cleaning procedure with a mandatory assessment of its purity. The purpose of this study was to develop simple, express, selective methods for luminescent determination of residual quantities of APIs of trazodone hydrochloride (TG) and melatonin (MT) in washes to control the completeness of their removal when cleaning process equipment. The excitation and luminescence spectra were recorded using a Cary Eclipse "Varian" spectrofluorimeter (Australia) with a xenon lamp 150 W. Electronic absorption spectra were recorded on a UV-2401 PC spectrophotometer «Shimadzu» (Japan). The electronic absorption spectra of TG and MT have absorption bands in the UV spectral region. It was established experimentally that the excitation spectra of TG and MT are similar to their absorption spectra (λex = 318 nm (TG) and λem = 274 nm (MT)). The effect on the luminescence intensity of TG and MT of methanol, ethanol, acetonitrile, dimethylformamide, dimethylsulfoxide, propanol (50 v/v) was studied. It is established that the maximum luminescence is observed in water. The methods were validated according to the following parameters: specificity, linearity, accuracy, limit of quantitation. The degree of extraction of trazodone hydrochloride and melatonin from applicators and surfaces of pharmaceutical equipment is more than 90%. The developed methods can be recommended for determining the residual amounts of trazodone hydrochloride and melatonin while monitoring the quality of the cleaning of pharmaceutical equipment.

A quantitative approach to inner shell losses

1978 ◽  
Vol 36 (1) ◽  
pp. 526-527 ◽  
Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers
Keyword(s):  
Energy Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Background Intensity ◽  
Core Excitation ◽  
Quantitative Basis ◽  
Cross Section Differential ◽  
Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

Fast calibration of CBED patterns for quantitative analysis

1993 ◽  
Vol 51 ◽  
pp. 674-675
Author(s):  
M.A. Gribelyuk ◽  
M. Rühle
Keyword(s):  
Reciprocal Lattice ◽  
Accurate Determination ◽  
Incident Beam ◽  
Crystal Thickness ◽  
Structure Model ◽  
Beam Direction ◽  
Transmitted Beam ◽  
Reciprocal Vector ◽  
On Line

A new method is suggested for the accurate determination of the incident beam direction K, crystal thickness t and the coordinates of the basic reciprocal lattice vectors V1 and V2 (Fig. 1) of the ZOLZ plans in pixels of the digitized 2-D CBED pattern. For a given structure model and some estimated values Vest and Kest of some point O in the CBED pattern a set of line scans AkBk is chosen so that all the scans are located within CBED disks.The points on line scans AkBk are conjugate to those on A0B0 since they are shifted by the reciprocal vector gk with respect to each other. As many conjugate scans are considered as CBED disks fall into the energy filtered region of the experimental pattern. Electron intensities of the transmitted beam I0 and diffracted beams Igk for all points on conjugate scans are found as a function of crystal thickness t on the basis of the full dynamical calculation.

Computer-Assisted High-Re Solution TEM

1990 ◽  
Vol 48 (1) ◽  
pp. 162-163
Author(s):  
F.A. Ponce ◽  
H. Hikashi
Keyword(s):  
Signal To Noise Ratio ◽  
Accurate Determination ◽  
Computer Software ◽  
Video Camera ◽  
Image Contrast ◽  
Objective Lens ◽  
Computer Assisted ◽  
Optical Parameters ◽  
Astigmatism Correction

The determination of the atomic positions from HRTEM micrographs is only possible if the optical parameters are known to a certain accuracy, and reliable through-focus series are available to match the experimental images with calculated images of possible atomic models. The main limitation in interpreting images at the atomic level is the knowledge of the optical parameters such as beam alignment, astigmatism correction and defocus value. Under ordinary conditions, the uncertainty in these values is sufficiently large to prevent the accurate determination of the atomic positions. Therefore, in order to achieve the resolution power of the microscope (under 0.2nm) it is necessary to take extraordinary measures. The use of on line computers has been proposed [e.g.: 2-5] and used with certain amount of success.We have built a system that can perform operations in the range of one frame stored and analyzed per second. A schematic diagram of the system is shown in figure 1. A JEOL 4000EX microscope equipped with an external computer interface is directly linked to a SUN-3 computer. All electrical parameters in the microscope can be changed via this interface by the use of a set of commands. The image is received from a video camera. A commercial image processor improves the signal-to-noise ratio by recursively averaging with a time constant, usually set at 0.25 sec. The computer software is based on a multi-window system and is entirely mouse-driven. All operations can be performed by clicking the mouse on the appropiate windows and buttons. This capability leads to extreme friendliness, ease of operation, and high operator speeds. Image analysis can be done in various ways. Here, we have measured the image contrast and used it to optimize certain parameters. The system is designed to have instant access to: (a) x- and y- alignment coils, (b) x- and y- astigmatism correction coils, and (c) objective lens current. The algorithm is shown in figure 2. Figure 3 shows an example taken from a thin CdTe crystal. The image contrast is displayed for changing objective lens current (defocus value). The display is calibrated in angstroms. Images are stored on the disk and are accessible by clicking the data points in the graph. Some of the frame-store images are displayed in Fig. 4.

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